Methodology of Unequal Risk investigation
Our data analysis behind the Unequal Risk investigation into work-related diseases in America.
CANCER RISK
Our interactive cancer-risk graphic is based on an analysis by Adam M. Finkel — a former director of OSHA’s health regulatory divisions who is now at the University of Pennsylvania Law School — and the Center for Public Integrity. It tackles a thorny question: If 1,000 workers are exposed to a chemical’s legal limit over their entire careers, how many will likely get cancer as a result of that exposure? What, in other words, is the excess risk above and beyond the cancer risk everyone faces?
First, an important note: Any risk analysis produces estimates, not exact numbers. Its value is showing how much hazards can vary under the law. (This analysis doesn’t look at average exposures, but rather the impact of what exposure at exactly the legal limit would be. But the Center also mined an OSHA inspections database for a separate analysis to find out how often the agency detected several toxic substances above the legal level. See the exposure-data section below for more on that.)
Our group of theoretical workers is 1,000-strong for a reason. OSHA considers a grave risk such as cancer that affects one worker in 1,000, all equally exposed over the length of their careers, to be “clearly significant.”
That means the agency should enact workplace standards that lead to less risk, particularly since OSHA says it doesn’t see 1 in 1,000 as the dividing line between too much and OK. But for all the years the agency has quantified risk — since the Supreme Court required it in 1980 — OSHA has never enacted a standard on the right side of that threshold, it says. Court decisions have made clear that limits must be set based on what is technologically and economically feasible — a hotly contested issue.
Americans enjoy much stronger federal protections from chemicals when they’re off the clock than on it. The U.S. Environmental Protection Agency, operating under different laws and court decisions, aims to protect the public so no more than one cancer case in 10,000 results from pollution in the community — and more often, no more than one in 1 million. On paper, that’s 10 to 1,000 times more protective.
What our analysis with Finkel suggests is that the actual difference is far worse. That’s because cancer risks at OSHA’s exposure limits are often much higher than 1 in 1,000.
The analysis relied on cancer-risk figures developed by the U.S. EPA and California’s EPA for certain known or likely human carcinogens. These “inhalation unit risk” figures allow researchers to calculate cancer risk over a lifetime of community exposure at a specified level. We adjusted these figures to account for on-the-job exposure: 40 years instead of 70, 50 weeks a year instead of 52, five days a week instead of seven and the amount of air inhaled by the typical employee during a workday compared with a resident off work all day (10 cubic meters of air vs. 20, which takes into account both the difference in hours and breathing rates).
There’s more to this story. Click here to read the rest at the Center for Public Integrity.
This story is part of Unequal risk. Workers in America face risks from toxic exposures that would be considered unacceptable outside the job. Click here to read more stories in this blog.
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Copyright 2015 The Center for Public Integrity. This story was published by The Center for Public Integrity, a nonprofit, nonpartisan investigative news organization in Washington, D.C.
